Tactile sensor

Abstract

A tactile area sensor for robots has an array of pneumatic flow passages. The air flow in each passage is dependent on a localized force exerted by an object pressing against an elastic pad on the face of the sensor. The air flow impinges on a metallic tab and its angular displacement is sensed by directing a light beam from an optical fiber onto the tab and monitoring the quantity of light reflected to a paired optical fiber. The array of optical outputs can be presented to a charge injection device and are dependent on the shape of the object.

The invention claimed is: 
     
       1. A tactile area sensor comprising: a continuous elastic pad attached to a first surface of a rigid pneumatic subassembly;   said pneumatic subassembly having an array of separate passages for the flow of gas from a common source to an exit port for each passage, the individual passages extending to said first surface so that an object pressing into said elastic pad exerts forces which result in deflections of said elastic pad and variably restricts gas flow through said passages; and   output means adjacent to every exit port for sensing the quantity of gas flow and developing an array of optical outputs which are dependent on the force distribution and thus the shape of the object.   
     
     
       2. The tactile sensor of claim 1 wherein said output means includes an array of resilient tabs mounted above said exit ports that are angularly deflected dependent on the gas flow from the associated exit port. 
     
     
       3. The tactile sensor of claim 2 wherein said output means further includes a pair of optical fibers supported above every resilient tab for directing a beam of light onto said tab and for capturing reflected light. 
     
     
       4. The tactile sensor of claim 1 wherein said pneumatic subassembly has a plenum passage adjacent to a second surface and every separate flow passage consists of a first passage extending from said plenum to an interconnecting passage parallel to said first surface and hence to a second passage which exits at said second surface. 
     
     
       5. A tactile area sensor comprising: a continuous elastic pad attached to a first major surface of a rigid pneumatic subassembly;   said pneumatic subassembly having an array of separate passages in columns and rows for the flow of air from a common source to an exit port for each passage on a second major surface of said subassembly, the individual passages extending to said first major surface so than an object pressing into said elastic pad exerts forces which result in deflections of said elastic pad and variably restricts air flow through said passages;   an array of resilient light reflective tabs mounted parallel to the second major surface of said pneumatic subassembly to be angularly deflected dependent on the air flow exiting from the associated passage; and   optical fibers supported above said tabs for directing a beam of light onto each tab and capturing reflected light from the tab, the quantity of captured reflected light being indicative of the force exerted by the object and thus its shape.   
     
     
       6. The tactile sensor of claim 5 wherein said pneumatic subassembly has a plenum passage adjacent to said second surface and every separate flow passage consists of a first passage extending from said plenum to an interconnecting passage parallel to said first surface and hence to a second passage which terminates at said exit port. 
     
     
       7. The tactile sensor of claim 6 wherein said pneumatic subassembly has a laminated construction and is comprised of at least four etched metal laminations. 
     
     
       8. The tactile sensor of claim 7 wherein said array of tabs are on another metal lamination.